1. Field of the Invention
This invention relates to an automatic exposure control camera, and more particularly to a photographic camera with an exposure control means wherein the aperture size of a diaphragm and the shutter speed are freely selected and the density of a filter is automatically controlled in accordance with the scene brightness.
2. Description of the Prior Art
In the conventional automatic exposure control camera, either the aperture size of a diaphragm or the shutter speed is freely selected in advance and the remaining one is automatically controlled by use of an exposure control circuit. In addition to this ordinary type of the automatic exposure control camera, it has also been known in the art to automatically select a combination of the aperture size and shutter speed from a group of predetermined combinations thereof in accordance with the scene brightness measured by use of an exposure measuring circuit and an exposure control circuit connected therewith. In these conventional automatic exposure control cameras, only two variables, i.e. the aperture size and the shutter speed, are used to determine the exposure. The film sensitivity is of course introduced into the exposure control means as input information to determine the exposure. Therefore, if one of the two variables is preselected, the other is automatically determined by the exposure control means.
However, in the photographic technique, the aperture size has an important role in addition to that of exposure control, namely, that of determining the focal depth. Further, the shutter speed also has an important role in addition to that of exposure control, namely, that of determining the degree of blur. Therefore, it is desirable to freely select both the aperture size and the shutter speed to obtain a photograph of desirable sharpness and blur. As described hereinabove, in the conventional photographic cameras with an exposure control means, it has been impossible to freely select both the aperture size and the shutter speed.